Chris Rogers, Whitbread's experienced finance director, is to take over direct control of the group's strong-performing Costa Coffee business in a boardroom reshuffle that appears to prepare the espresso chain for a sale or flotation.

Once a sprawling leisure empire rapidly constructed on the foundations of Whitbread's brewing legacy in the 1990s, the group has been dramatically slimmed down and now comprises just three divisions – Premier Inn, Costa Coffee and a pub restaurants arm including Beefeater and Brewers Fayre.

While the pubs, restaurants and budget hotels are paired alongside each other, making for a well-integrated business, the same is not true for Costa. The coffee business, for the last six years run by John Derkach, operates as a very separate business unit and there has been speculation for some time that it would be spun off.

The chief executive, Andy Harrison, said: "There is no hidden agenda here. The announcement was driven by John's decision to join Tragus [the private equity-backed firm behind Strada, Cafe Rouge and Bella Italia]. And the decision to appoint Chris is because he is the best man for the job."

Asked about the possibility of demerging Costa, Harrison said: "Whitbread is a great owner of Costa and the business continues to perform well for shareholders." But he added: "The future is a long time and we have always said: 'Never say never'."

Operating in a rare growth market on the high street, Costa is one of Britain's few chains in expansion mode. The business has 1,375 UK stores, 920 Costa Express vending machines and a further 800 shops overseas.

Whitbread's previous chief executive, Alan Parker, who stepped down in late 2010, had steadily dismantled much of the leisure empire, a conglomerate of the type that had fallen out of fashion with City investors. Among the businesses that were sold were the UK franchise operations of Marriott Hotels, Pizza Hut and TGI Friday's. Gone too are David Lloyd Leisure, most of Whitbread's pubs and the group's share in Pepsi bottling group Britvic.

Derkach will leave in August to join Tragus, the restaurant group backed by private equity house Blackstone. He will replace long-standing chief executive Graham Turner and arrives following a refinancing last month of the group's debts. Blackstone agreed to convert some of its loans to Tragus into equity to relieve pressure on the firm's balance sheet. Net debt at the firm, which runs almost 300 restaurants, was reduced from £240m to £219m as a result.

Geof Colyer, an analyst at Deutsche bank, Whitbread's house broker, played down the likelihood of a Costa demerger. "If demerger was a near-term option why is the managing director leaving? We see an early demerger of Costa as potentially limited the realisable value from the Costa growth plans for investors." However, he added that the implied value of Costa in Whitbread's share price was too low. "We estimate that the implied value is barely five times earnings before interest, tax, depreciation and amortisation."